Typically for vehicular communications a quarter wave vertical antenna rod is mounted vertically above a ground plane formed by a sheet metal body region, usually on rooftop or rear deck locations which have been found to provide efficient operation. Such an antenna may be considered unsightly when the vehicle is also used part time for private purposes. In unmarked law enforcement vehicles, high visibility of a conventional communications antenna and associated mounting hardware clearly poses a serious disadvantage. Conventional antenna mountings do not lend themselves to easy removal or concealment: either the antenna is not readily removable, or the mounting, which must be securely bonded to the metal car body for reasons of RF grounding integrity, may still leave telltale pieces of hardware exposed when the antenna rod is removed.
A transverse baseplate type antenna mounting assembly such as that disclosed in U.S. Pat. No. 4,184,160, which is secured in place by screw means, would be inconvenient to remove and replace, and would be bulky and awkward to store in the vehicle while removed.
Furthermore, it would be highly advantageous to be able to remove or conceal the antenna from within the vehicle; this is impossible in known antenna mounting configurations. Well known auto radio receiver antenna configurations of the retractable telescopic type are deemed unsuitable for two way radio communications purposes, and are generally conspicuous even when retracted.
With the regular antenna removed or concealed, there will usually be a need to conduct further communications; however this is normally impossible with the external antenna element removed.
It has been found empirically that an antenna located within vehicle, despite the partial shielding effect of the metal vehicle body, will radiate sufficiently through openings such as windows to provide useful communications despite some reduction in radiated field strength which limits the useable distance range. Known communication antenna mounting configurations fail to provide for deployment within the vehicle, and have otherwise generally failed to anticipate or address the problems which have been identified and solved by the present invention.